Thread cutting tool



T. BRIEGEL THREAD CUTTING TOOL Filed Sept. 26, 1938 Oct. 24, 1939.

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Patented Oct. 24, 1939 UNITED STATES PATENT OFFICE 1 Claim.

My invention has reference to a thread cutting machine, and has to do more specially with the forming of threads on tubing and pipes of lighter construction. In the present practice 5 the thread is cut for a greater length than required, so that a portion of the tubing which has been weakened by having threads cut therein, and which extends past a point of support, is in danger of bending or breaking at such point.

lo The chief purpose of the present invention is to provide a tool wherein the length of the threaded portion is predetermined, and limited to the special use for which the tube or pipe is intended.

Another purpose of the invention is to provide 15 means for the guidance of pieces of tubing into the tool, and means for adapting the same for use with material of diierent diameters, The cutting dies are also arranged so as to be removed and replaced by others for operation on a tube 20 of stated diameter, and with a variation in the amount of thread cut, if desired.

The above named, and other features and advantages of the invention will more fully appear from the following-specification, reference being 25 had to the accompanying drawing, in which;

Fig. 1 is a front view of the invention.

Fig. 2 is a medial longitudinal section thereof.

Fig. 3 is a view from the rear, with some of the parts removed.

Fig. 4 is a detail of the tube guiding devices.

The reference number 5 indicates the circular body portion of a threading tool, provided at opposite sides with sockets I5, in which are held the ends of rods 1, for use as handles in rotating 35 the tool. Within said head is a cavity 8, containing a die 9, of the usual thread-cutting type, the chips and cuttings from which are permitted to escape through openings I in the front wall II of the head. The die 9 is held from rotating 40 by a pin I2, xed in the head, and engaging a groove I3 in the periphery of the die. Said pin also serves as a gauge, to properly position different dies that may be used in the tool.

' Projected from the cavity 8 is a recess I4, in

45 the inner part of which is an -annular channel I5, from which openings I6 extend to the rear wall of the head. Said openings are equidistant from each other, and are adapted to receive lugs I1 on the head I8 of a cylindrical guide member 50 I9. By inserting said lugs in the openings and .giving a partial rotation to the guide I9 the lugs are brought to points in the channel I where they will be held from release, as indicated in Fig. 3, and the guide I9 will be retained in position, coupled 55 with the body portion 5. A pin 20 against which one of the lugs contacts serves as a stop therefor,

and limits the movement of the head I8 in one direction. At the opposite side of the tool there is fixed to the body portion a small spring ZI, carrying alatch-pin 22, which drops down in rear of one of the lugs Il, and prevents a return move- 5 ment thereof. The tool can thereupon be turned in either direction, in the Work of forming a series of threads on a piece of tubing or other object.

As shown in Fig. 2, the guide member is shown 10 provided with an extra sleeve 23, provided on its inner end with an annular flange 24, held in a recess 25 in the head I8. By this means the diameter of the guide can be varied, to receive a piece of tubing of a fixed size, such as is shown at 26, provided on its end with a thread 21. The bores of the guide I9 and sleeve 23 are of predetermined diameters, to provide supporting means and guides for tubing of substantially the same diameter. An additional sleeve of still smaller diameter can be substituted for the sleeve 23 if desired, and other variations can be taken care of by changing the size of the tool.

The dies 9 can also be changed to conform to the diameter of the tube, at such times as the guide member I9 is not in place in the tool. Said guide member can be dislodged by raising the vspring 2! and pin 22 and turning the head I8 to a point to permit the passage of the lugs I1 through the openings I6. 80

It will be noted that movement of the end of the tube 25 inwardly is limited by coming in contact with the front wall II of the tool, and that the amount of thread to be cut on the end of the tube is similarly limited, and is no greater than the thickness of the die. The thickness of the die can also be increased by forming the head I8 of thinner metal than is set forth herein.

The piece of tubing shown may be of that kind which is known as thin wall tubing, which is more easily weakened by the cutting of threads therein than that of a heavier type, but it is not necessarily limited thereto.

What I claim, and desire to secure, is:

A device of the class described, comprising a body portion including a front plate, a back plate detachably connected therewith, a tubular guide member projecting from said back plate, one or more tubular members adapted for being positioned in said guide member, to receive and guide parts for a threading operation, and thread cutting dies between said plates, the spacing between said plates determining the width of out on the part presented for threading.

THEODORE BRIEGEL. 

